Do not include fileBrowserHandler schema definition in non-chromeos.

chrome/common/extensions/api/BUILD.gn

Index: chrome/common/extensions/api/BUILD.gn
diff --git a/chrome/common/extensions/api/BUILD.gn b/chrome/common/extensions/api/BUILD.gn
index cd8827217752b4f5075ca082ddaf1b4a38bed749..905fa27cb8f82a8b958a6d67bdb4c6366d725c45 100644
--- a/chrome/common/extensions/api/BUILD.gn
+++ b/chrome/common/extensions/api/BUILD.gn
@@ -175,7 +175,6 @@ json_schema_api("api") {
     "browser_action.json",
     "commands.json",
     "declarative_content.json",
-    "file_browser_handler.json",
     "page_action.json",
     "privacy.json",
     "proxy.json",
@@ -184,7 +183,9 @@ json_schema_api("api") {
     "types_private.json",
     "webstore.json",
   ]
-  if (!is_chromeos) {
+  if (is_chromeos) {
+    uncompiled_bundle_schema_sources += [ "file_browser_handler.json" ]
+  } else {
     # On ChromeOS, input_method_private is fully compiled (as part of
     # schema_files), and so gets added to the bundle already. On other
     # platforms, we still need it added to the bundle.